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Stock SP, Hazir S. The bacterial symbionts of Entomopathogenic nematodes and their role in symbiosis and pathogenesis. J Invertebr Pathol 2025:108295. [PMID: 40032241 DOI: 10.1016/j.jip.2025.108295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2024] [Revised: 02/20/2025] [Accepted: 02/26/2025] [Indexed: 03/05/2025]
Abstract
Entomopathogenic bacteria in the genera Xenorhabdus and Photorhabdus are mutualistically associated with entomopathogenic nematodes (EPN) Steinernema and Heterorhabditis, respectively. Together they form an insecticidal partnership which has been shown to kill a wide range of insect species. The spectrum of dependence in this symbiotic partnership is diverse, ranging from a tight, obligate relationship to a facultative one. A body of evidence suggests that the reproductive fitness of the nematode-bacterium partnership is tightly associated and interdependent. Furthermore, maintenance of their virulence is also critical to the conversion of the insect host as a suitable environment where this partnership can be perpetuated. Disruption of the symbiotic partnership can have detrimental effects on the fitness of both partners. The nematode-bacterial symbiont-insect partnership represents a model system in ecology and evolutionary biology and amenable to investigate beneficial and antagonistic interactions between invertebrates and microbes. Furthermore, the EPN's bacterial symbionts are also viewed as a model system to study the biosynthesis, structure and function of various natural products. Their ability to produce up to 25 different natural product classes is outstanding among the Morganellaceae. These natural products show biological activity, most likely originating from important functions during the life cycle of both the nematodes and their symbionts. Tools and high throughput technologies have been developed to identify ubiquitous and rare molecules and study their function and assess their potential as novel biological activities. We herein summarize the symbiotic relationship between EPN and their bacterial symbionts, focusing on their fitness and their ability to successfully access and utilize an insect host. We also recapitulate the history of natural products research highlighting recent findings and the synthetic biology approaches that are currently implemented to identify non-natural derivatives from Xenorhabdus and Photorhabdus with improved biological activity.
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Affiliation(s)
- S Patricia Stock
- Department of Horticulture, Oregon State University, Agriculture and Life Sciences Bldg. Rm 4007B 2750 SW Campus Way, Corvallis, OR 97331, USA.
| | - Selçuk Hazir
- Aydin Adnan Menderes University, Faculty of Science, Department of Biology, Aydin, Turkey
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Palma L, Frizzo L, Kaiser S, Berry C, Caballero P, Bode HB, Del Valle EE. Genome Sequence Analysis of Native Xenorhabdus Strains Isolated from Entomopathogenic Nematodes in Argentina. Toxins (Basel) 2024; 16:108. [PMID: 38393187 PMCID: PMC10892061 DOI: 10.3390/toxins16020108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/05/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
Entomopathogenic nematodes from the genus Steinernema (Nematoda: Steinernematidae) are capable of causing the rapid killing of insect hosts, facilitated by their association with symbiotic Gram-negative bacteria in the genus Xenorhabdus (Enterobacterales: Morganellaceae), positioning them as interesting candidate tools for the control of insect pests. In spite of this, only a limited number of species from this bacterial genus have been identified from their nematode hosts and their insecticidal properties documented. This study aimed to perform the genome sequence analysis of fourteen Xenorhabdus strains that were isolated from Steinernema nematodes in Argentina. All of the strains were found to be able of killing 7th instar larvae of Galleria mellonella (L.) (Lepidoptera: Pyralidae). Their sequenced genomes harbour 110 putative insecticidal proteins including Tc, Txp, Mcf, Pra/Prb and App homologs, plus other virulence factors such as putative nematocidal proteins, chitinases and secondary metabolite gene clusters for the synthesis of different bioactive compounds. Maximum-likelihood phylogenetic analysis plus average nucleotide identity calculations strongly suggested that three strains should be considered novel species. The species name for strains PSL and Reich (same species according to % ANI) is proposed as Xenorhabdus littoralis sp. nov., whereas strain 12 is proposed as Xenorhabdus santafensis sp. nov. In this work, we present a dual insight into the biocidal potential and diversity of the Xenorhabdus genus, demonstrated by different numbers of putative insecticidal genes and biosynthetic gene clusters, along with a fresh exploration of the species within this genus.
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Affiliation(s)
- Leopoldo Palma
- Instituto de Biotecnología y Biomedicina (BIOTECMED), Departamento de Genética, Universitat de València, 46100 Burjassot, Spain
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires C1033AAJ, Argentina
- Instituto Multidisciplinario de Investigación y Transferencia Agroalimentaria y Biotecnológica (IMITAB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Villa María (UNVM), Villa María 1555, Argentina
| | - Laureano Frizzo
- ICIVET Litoral, CONICET-UNL, Departamento de Salud Pública, Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, Esperanza S3080, Argentina;
| | - Sebastian Kaiser
- Department of Natural Products in Organismic Interactions, Max-Planck-Institute for Terrestrial Microbiology, 35043 Marburg, Germany; (S.K.); (H.B.B.)
- Evolutionary Biochemistry Group, Max-Planck-Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Colin Berry
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK;
| | - Primitivo Caballero
- Institute for Multidisciplinary Research in Applied Biology, Universidad Pública de Navarra, 31006 Pamplona, Spain;
- Departamento de Investigación y Desarrollo, Bioinsectis SL, Polígono Industrial Mocholi Plaza Cein 5, Nave A14, 31110 Noain, Spain
| | - Helge B. Bode
- Department of Natural Products in Organismic Interactions, Max-Planck-Institute for Terrestrial Microbiology, 35043 Marburg, Germany; (S.K.); (H.B.B.)
- Molecular Biotechnology, Department of Biosciences, Goethe Universität Frankfurt, 60438 Frankfurt, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Phillips University Marburg, 35043 Marburg, Germany
- Department of Chemistry, Phillips University Marburg, 35043 Marburg, Germany
- Senckenberg Gesellschaft für Naturforschung, 60325 Frankfurt, Germany
| | - Eleodoro Eduardo Del Valle
- ICiagro Litoral, CONICET, Facultad de Ciencias Agrarias, Universidad Nacional del Litoral, Kreder 2805, Esperanza S3080, Argentina
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Trejo-Meléndez VJ, Méndez-López TT, Contreras-Garduño J. The Coincidental Evolution of Virulence Partially Explains the Virulence in a Generalist Entomopathogenic. Acta Parasitol 2023:10.1007/s11686-023-00663-4. [PMID: 36806112 DOI: 10.1007/s11686-023-00663-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 01/16/2023] [Indexed: 02/23/2023]
Abstract
PURPOSE The parasites' virulence is labile after jumping to a new host species, and it might derivate in gaining virulence against a new host as a side effect of living in a non-host environment (coincidental evolution of virulence hypothesis). METHODS To test this hypothesis, we monitored the experimental evolution of the Rhabditis regina nematode for over 290 generations (4 years) in three environments (strains): (1) the natural host, Phyllophaga polyphylla, (2) an alternate host, Tenebrio molitor, and (3) saprophytic medium (beef; the food that may provide evidence for the coincidental evolution of virulence). Each strain was exposed to P. polyphylla, T. molitor, or Galleria mellonella. We compared the host survival and immune response (proPO, PO, and lytic activity) of infected versus uninfected hosts. RESULTS The saprophytic nematodes gained virulence only against G. mellonella. However, the P. polyphylla strain was more effective in killing P. polyphylla than T. molitor, and the T. molitor strain was more effective against T. molitor than P. polyphylla. Additionally, one dauer larva was sufficient to kill the hosts. Finally, the immune response did not differ between the challenged and control groups. CONCLUSION The coincidental evolution of virulence partially explains our results, but they might also support the short-sighted hypothesis. Additionally, we found evidence for immunomodulation because nematodes passed unnoticed to the immune response. It is crucial to analyze the virulence of entomopathogens from the point of view of the evolution of virulence to be aware of potential scenarios that might limit biological control.
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Affiliation(s)
- Víctor José Trejo-Meléndez
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Av. Ciudad Universitaria 3000, C.P. 04510, Coyoacán, CDMX, Mexico
- ENES, Unidad Morelia, UNAM. Antigua Carretera a Pátzcuaro No.8701. Col. Ex-Hacienda San José de la Huerta Código Postal 58190, Morelia, Michoacán, Mexico
| | - Texca T Méndez-López
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Av. Ciudad Universitaria 3000, C.P. 04510, Coyoacán, CDMX, Mexico
- ENES, Unidad Morelia, UNAM. Antigua Carretera a Pátzcuaro No.8701. Col. Ex-Hacienda San José de la Huerta Código Postal 58190, Morelia, Michoacán, Mexico
| | - Jorge Contreras-Garduño
- ENES, Unidad Morelia, UNAM. Antigua Carretera a Pátzcuaro No.8701. Col. Ex-Hacienda San José de la Huerta Código Postal 58190, Morelia, Michoacán, Mexico.
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Hlávková D, Skoková Habuštová O, Půža V, Vinokurov K, Kodrík D. Role of adipokinetic hormone in the Colorado potato beetle, Leptinotarsa decemlineata infected with the entomopathogenic nematode Steinernema carpocapsae. Comp Biochem Physiol C Toxicol Pharmacol 2022; 262:109466. [PMID: 36108997 DOI: 10.1016/j.cbpc.2022.109466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/24/2022] [Accepted: 09/08/2022] [Indexed: 11/17/2022]
Abstract
The effects of the entomopathogenic nematode Steinernema carpocapsae on the Colorado potato beetle (CPB) Leptinotarsa decemlineata and the involvement of adipokinetic hormone (AKH) in the responsive reactions were examined in this study. It was observed that nematode application doubled the amount of AKH (Peram-CAH-I and Peram-CAH-II) in the central nervous system of L. decemlineata, indicating mobilization of anti-stress reactions in the body. Furthermore, the external co-application of Peram-CAH-II with the nematode significantly increased beetle mortality (5.6 and 1.8 times, 1 and 2 days after application, respectively). The mechanism underlying this phenomenon was investigated. As the effect on gut characteristics was equivocal, it was assumed that the nematodes profited from the observed mobilization of metabolites from the fat body into the Peram-CAH-II-induced hemolymph. This phenomenon supplied nematodes with a more nutrient-dense substrate on which they propagated. Furthermore, Peram-CAH-II lowered vitellogenin expression in the fat body, particularly in males, thus limiting the anti-pathogen defense capacity of the protein. However, there could be other possible mechanisms underpinning this chain of events. The findings could be theoretically intriguing but could also aid in developing real insect pest control methods in the future.
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Affiliation(s)
- Daniela Hlávková
- Institute of Entomology, Biology Centre, CAS, Branišovská 31, 370 05 České Budějovice, Czech Republic; Faculty of Science, University of South Bohemia, Branišovská 31a, 370 05 České Budějovice, Czech Republic
| | - Oxana Skoková Habuštová
- Institute of Entomology, Biology Centre, CAS, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Vladimír Půža
- Institute of Entomology, Biology Centre, CAS, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Konstantin Vinokurov
- Institute of Entomology, Biology Centre, CAS, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Dalibor Kodrík
- Institute of Entomology, Biology Centre, CAS, Branišovská 31, 370 05 České Budějovice, Czech Republic; Faculty of Science, University of South Bohemia, Branišovská 31a, 370 05 České Budějovice, Czech Republic.
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Cortés-Martínez CI, Chavarría-Hernández N. Production of entomopathogenic nematodes in submerged monoxenic culture: A review. Biotechnol Bioeng 2020; 117:3968-3985. [PMID: 32710642 DOI: 10.1002/bit.27515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 01/29/2023]
Abstract
Monoxenic liquid culture is the most suitable technology for scaling up to industrial production of entomopathogenic nematodes (EPNs); however, the variability of the yield production remains a current problem in the process. The aim of this study was to analyze the parameters and criteria for EPN production in liquid culture based on scientific and technological knowledge from the last two decades. While experimental research has permitted the yield production of Heterorhabditis bacteriophora (362 × 103 infective juveniles [IJs]/ml) and Steinernema carpocapsae (252 × 103 IJs/ml), simultaneously, theoretical approaches have contributed to the understanding of the culture process, based on biological parameters of the bacterium-nematode complex and hydrodynamic and rheological parameters of the complex gas-liquid-solid system. Under this interdisciplinary research approach, bioprocess and biosystem engineering can contribute to design the various control strategies of the process variables, increase the productivity, and reduce the variability that until now distinguishes the in vitro production of EPNs by the liquid culture.
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Affiliation(s)
- Carlos Inocencio Cortés-Martínez
- Cuerpo Académico de Biotecnología Agroalimentaria, Instituto de Ciencias Agropecuarias, Universidad Autónoma del Estado de Hidalgo, Tulancingo de Bravo, Hidalgo, México
| | - Norberto Chavarría-Hernández
- Cuerpo Académico de Biotecnología Agroalimentaria, Instituto de Ciencias Agropecuarias, Universidad Autónoma del Estado de Hidalgo, Tulancingo de Bravo, Hidalgo, México
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Fujdiarová E, Houser J, Dobeš P, Paulíková G, Kondakov N, Kononov L, Hyršl P, Wimmerová M. Heptabladed β‐propeller lectins PLL2 and PHL from
Photorhabdus
spp. recognize
O
‐methylated sugars and influence the host immune system. FEBS J 2020; 288:1343-1365. [DOI: 10.1111/febs.15457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 04/19/2020] [Accepted: 06/15/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Eva Fujdiarová
- Central European Institute of Technology (CEITEC) Masaryk University Brno Czech Republic
- National Centre for Biomolecular Research Faculty of Science Masaryk University Brno Czech Republic
| | - Josef Houser
- Central European Institute of Technology (CEITEC) Masaryk University Brno Czech Republic
- National Centre for Biomolecular Research Faculty of Science Masaryk University Brno Czech Republic
| | - Pavel Dobeš
- National Centre for Biomolecular Research Faculty of Science Masaryk University Brno Czech Republic
- Section of Animal Physiology and Immunology Department of Experimental Biology Faculty of Science Masaryk University Brno Czech Republic
| | - Gita Paulíková
- Central European Institute of Technology (CEITEC) Masaryk University Brno Czech Republic
- National Centre for Biomolecular Research Faculty of Science Masaryk University Brno Czech Republic
| | - Nikolay Kondakov
- N.D. Zelinsky Institute of Organic Chemistry Russian Academy of Sciences Moscow Russia
| | - Leonid Kononov
- N.D. Zelinsky Institute of Organic Chemistry Russian Academy of Sciences Moscow Russia
| | - Pavel Hyršl
- Section of Animal Physiology and Immunology Department of Experimental Biology Faculty of Science Masaryk University Brno Czech Republic
| | - Michaela Wimmerová
- Central European Institute of Technology (CEITEC) Masaryk University Brno Czech Republic
- National Centre for Biomolecular Research Faculty of Science Masaryk University Brno Czech Republic
- Department of Biochemistry Faculty of Science Masaryk University Brno Czech Republic
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Kodrík D, Ibrahim E, Gautam UK, Frydrychová RČ, Bednářová A, Krištůfek V, Jedlička P. Changes in vitellogenin expression caused by nematodal and fungal infections in insects. J Exp Biol 2019; 222:jeb.202853. [DOI: 10.1242/jeb.202853] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 04/24/2019] [Indexed: 01/05/2023]
Abstract
This study examined the expression and role of vitellogenin (Vg) in the body of the firebug Pyrrhocoris apterus (Heteroptera, Insecta) during the infection elicited by two entomopathogenic organisms, the nematode Steinernema carpocapsae and the fungus Isaria fumosorosea. Infection by S. carpocapsae significantly up-regulated Vg mRNA expression in the male body. The corresponding increase in Vg protein expression was also confirmed by electrophoretic and immunoblotting analyses. Remarkably, in females, the tendency was opposite. Nematodal infection significantly reduced both Vg mRNA and Vg protein expression levels in fat body and hemolymph, respectively. We speculate that infection of reproductive females reduces Vg expression to the level, which is still sufficient for defense, but insufficient for reproduction. This circumstance reduces energy expenditure and helps the individual to cope with the infection. Importantly, purified Vg significantly inhibited growth of Xenorhabdus spp., an entomotoxic bacteria isolated from S. carpocapsae. However, the effect of Vg against I. fumosorosea was not so obvious. The fungus significantly stimulated Vg gene expression in males, however, a similar increase was not recapitulated on the protein level. Nevertheless, in females, both mRNA and protein Vg levels were significantly reduced after the fungal infection. The obtained data demonstrate that Vg is likely an important defense protein, possibly with a specific activity. This considerably expands the known spectrum of Vg functions, as its primary role was thought to be limited to regulating egg development in the female body.
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Affiliation(s)
- Dalibor Kodrík
- Institute of Entomology, Biology Centre, CAS, Branišovská 31, 370 05 České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Emad Ibrahim
- Institute of Entomology, Biology Centre, CAS, Branišovská 31, 370 05 České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 31, 370 05 České Budějovice, Czech Republic
- Faculty of Agriculture, University of Cairo, Giza, Egypt
| | - Umesh K. Gautam
- Institute of Entomology, Biology Centre, CAS, Branišovská 31, 370 05 České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | | | - Andrea Bednářová
- Faculty of Science, University of South Bohemia, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Václav Krištůfek
- Institute of Soil Biology, Biology Centre, CAS, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Pavel Jedlička
- Institute of Biophysics, CAS, Královopolská 135, 612 65 Brno, Czech Republic
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Kumar R, Kushwah J, Ganguly S, Garg V, Somvanshi VS. Proteomic Investigation of Photorhabdus Bacteria for Nematode-Host Specificity. Indian J Microbiol 2016; 56:361-367. [PMID: 27407301 DOI: 10.1007/s12088-016-0594-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/05/2016] [Indexed: 01/17/2023] Open
Abstract
Majority of animals form symbiotic relationships with bacteria. Based on the number of bacterial species associating with an animal, these symbiotic associations can be mono-specific, relatively simple (2-25 bacterial species/animal) or highly complex (>10(2)-10(3) bacterial species/animal). Photorhabdus (family-Enterobacteriaceae) forms a mono-specific symbiotic relationship with the entomopathogenic nematode Heterorhabditis. This system provides a tractable genetic model for animal-microbe symbiosis studies. Here, we investigated the bacterial factors that may be responsible for governing host specificity between nematode and their symbiont bacteria using proteomics approach. Total protein profiles of P. luminescens ssp. laumondii (host nematode- H. bacteriophora) and P. luminescens ssp. akhurstii (host nematode- H. indica) were compared using 2-D gel electrophoresis, followed by identification of differentially expressed proteins by MALDI-TOF MS. Thirty-nine unique protein spots were identified - 24 from P. luminescens ssp. laumondii and 15 from P. luminescens ssp. akhurstii. These included proteins that might be involved in determining host specificity directly (for e.g. pilin FimA, outer membrane protein A), indirectly through effect on bacterial secondary metabolism (for e.g. malate dehydrogenase Mdh, Pyruvate formate-lyase PflA, flavo protein WrbA), or in a yet unknown manner (for e.g. hypothetical proteins, transcription regulators). Further functional validation is needed to establish the role of these bacterial proteins in nematode-host specificity.
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Affiliation(s)
- Ram Kumar
- Division of Nematology, ICAR- Indian Agricultural Research Institute, Pusa Campus, New Delhi, 110012 India.,ICAR-National Research Center on Plant Biotechnology, Pusa Campus, New Delhi, 110012 India
| | - Jyoti Kushwah
- Division of Nematology, ICAR- Indian Agricultural Research Institute, Pusa Campus, New Delhi, 110012 India
| | - Sudershan Ganguly
- Division of Nematology, ICAR- Indian Agricultural Research Institute, Pusa Campus, New Delhi, 110012 India
| | - Veena Garg
- Department of Biotechnology and Biosciences, Banasthali Vidyapeeth, Jaipur, Rajasthan India
| | - Vishal S Somvanshi
- Division of Nematology, ICAR- Indian Agricultural Research Institute, Pusa Campus, New Delhi, 110012 India
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Inman Iii FL, Holmes L. Antibacterial Screening of Secreted Compounds Produced by the Phase I Variant of Photorhabdus luminescens. Indian J Microbiol 2013; 52:708-9. [PMID: 24293735 DOI: 10.1007/s12088-012-0307-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 09/17/2012] [Indexed: 10/27/2022] Open
Abstract
In this study, antibacterial activity of metabolites secreted by the phase I variant of Photorhabdus luminescens was investigated. Bioactivity of these metabolites was screened against 28 different bacterial species and strains. Bacterial sensitivity was determined by a modified-version of the Kirby-Bauer disk diffusion susceptibility method, whereas the phase I variant's culture permeate was utilized as the "antibacterial" agent. This investigation demonstrates that 11 of the 28 bacterial species tested were sensitive to at least one of the secreted compounds or a combination thereof.
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Affiliation(s)
- Floyd L Inman Iii
- Sartorius-Stedim Biotechnology Laboratory, Biotechnology Research and Training Center, University of North Carolina at Pembroke, 115 Livermore Drive, Pembroke, NC 28372 USA
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Inman FL, Holmes L. Effect of heat sterilization on the bioactivity of antibacterial metabolites secreted by Xenorhabdus nematophila. Pak J Biol Sci 2012; 15:997-1000. [PMID: 24199479 DOI: 10.3923/pjbs.2012.997.1000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Photorhabdus luminescens and Xenorhabdus nematophila are entomopathogenic bacterial symbionts of beneficial nematodes Heterorhabditis bacteriophora and Steinernema carpocapsae, respectively. These bacterial symbionts are known to secrete an array of toxins, enzymes and antimicrobials that kill, bioconvert and protect the insect host for optimal nematode growth and reproduction. The present study explores heat stability of antibacterial metabolites secreted by X. nematophila. Permeate of a liquid X. nematophila culture was subjected to various sterilization treatments to observe the effects of heat sterilization on antibacterial activity. Activity was measured as bacterial sensitivity which is assayed utilizing a modified-version of the Kirby-Bauer disk diffusion method. Results demonstrate that X. nematophila produces both heat-labile and heat-stabile antibacterials that are effective against different species of bacteria. Results also indicated that heat-stabile components are more active than heat-labile components. The discovery of an environmental organism that produces both heat-stabile and heat-labile antibacterials can be exploited to manufacture these compounds for potential medical applications for human and animal use.
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Affiliation(s)
- Floyd L Inman
- Sartorius-stedim Biotechnology Laboratory, Biotechnology Research and Training Center, University of North Carolina at Pembroke, Pembroke, NC 28372, USA
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